1. Field of the Invention
The present invention relates to a pixel structure and a fabricating method thereof. More particularly, the present invention relates to a transflective pixel structure and a fabricating method thereof.
2. Description of Related Art
Nowadays, along with the great advancement of computer performance and the rapid development in Internet and multimedia technologies, the transmission of image information has been converted from analog signal transmission into digital signal transmission, and to meet customers' requirement, today's video or image apparatuses have become light, thin, and small. Conventional cathode ray tube (CRT) display has been leading the display market in recent years due to its excellent display quality and low cost. However, along with the rising consciousness of environmental conservation in recent years, CRT display has become unsatisfactory for it cannot meet the requirements of lightness, slimness, shortness, smallness, and low power consumption due to its high power consumption, high radiation, and its limitation in size reduction. Thus, flat panel displays based on optoelectronic technology and semiconductor manufacturing techniques, for example, liquid crystal display (LCD), organic light emitting diode (OLED), or plasma display panel (PDP), have become the mainstream of display market.
As described above, LCDs can be categorized into reflective LCD, transmissive LCD, and transflective LCD according to light source utility patterns thereof. For example, a transmissive or transflective LCD is mainly composed of a liquid crystal panel and a backlight module (B/L). Since the liquid crystal filled in the liquid crystal panel does not emit light itself, the backlight module has to provide a light for illuminating the liquid crystal panel so that the LCD can display images.
FIG. 1 is a diagram of a conventional transflective liquid crystal display (LCD) panel. Referring to FIG. 1, the LCD panel 100 includes an upper substrate 110, a lower substrate 120, a transflective plate 130, a liquid crystal layer 140, a pixel electrode 150, and a common electrode 160. The upper substrate 110 and the lower substrate 120 are opposite to each other. The liquid crystal layer 140 is disposed between the upper substrate 110 and the lower substrate 120, and the transflective plate 130 is disposed on the lower substrate 120. The pixel electrode 150 is disposed on the transflective plate 130. The pixel electrode 150 and the common electrode 160 disposed on the upper substrate 110 are used for modulating the arrangement of the liquid crystal layer 140. Besides, the transflective plate 130 reflects part of the external light and also allows part of the light provided by the backlight module (not shown) to pass through. Accordingly, the LCD panel 100 can perform both transmissive and reflective displays. However, the transmittance and reflectivity of the LCD panel 100 are limited by the transflective plate 130, and a color filter 170 still has to be disposed on the upper substrate 110 to provide colorful display. Thus, the LCD panel 100 has such disadvantages as insufficient brightness and low backlight utility.
FIG. 2 is a diagram of another conventional transflective LCD panel. Referring to FIG. 2, the LCD panel 200 includes an upper substrate 210, a lower substrate 220, a liquid crystal layer 240, a pixel electrode 250, and a common electrode 260. The various components of the LCD panel 200 are similar to those of the LCD panel 100, therefore similar numeral references are used and not described herein. The difference between the two LCD panels is that in the LCD panel 200, a reflective plate 230 is also disposed on part of the lower substrate 220 in order to define a reflective region R, and the region without the reflective plate 230 is a transmissive region T. The liquid crystal layer 240 is disposed between the upper substrate 210 and the lower substrate 220. The LCD panel 200 has a reflective display mode and a transmissive display mode. While displaying with only the reflective display mode, only the reflective region R in the LCD panel 200 displays. On the other hand, while displaying with only the transmissive display mode, only the transmissive region T in the LCD panel 200 displays. In short, the LCD panel 200 has very low aperture ratio in a single display mode, and accordingly the backlight utility and display quality of the LCD panel 200 are unsatisfying. Similarly, a color filter 270 has to be disposed on the substrate to provide colorful display, thus, light transmittance is low and the display quality of the LCD panel 200 is affected.
The backlight utility and aperture ratio of an existing transflective LCD have to be improved in order to allow the transflective LCD to provide better display quality.